Chain grate



Jan. 4 1927.

' 1,613,316 w. M. DUNCAN CHAIN GRATE Filed May 16v 1925 ill Patented Jan. 4, 1927.

UNTED STATES italiane PATENT iii..

CHAIN GRATE.

Application led May 16, 1925.

This invention relates to improvements in chain grates and more particularly to the links adapted to form a chain grate. One of the objects of the invention is to produce a simple and inexpensive chain grate wherein the draft serves as an effective cooling medium for the fuel-supporting portion of the grate, thereby preventing destructive overheating of the simple grate links. Another object is to improve the combustion by transmitting the draft to a relatively large portion of the fuel which contacts with the grate, and to more effectively distribute the draft through the fuel bed.

W'ith the foregoing and other objects in view, the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated in the accompanying drawings, wherein is shown the preferred embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended.

In the preferred form of the invention, each grate link is a simple casting enlarged at the top to provide a fuel-supporting rib, and having pivot-receiving bosses below said rib, the bosses being large enough to serve as spacers whereby the adjacent side faces of the fuel-supporting ribs are separated from each other to form draft inlet passages between them. The fuel-supporting ribs have inclined fuel-receiving surfaces extending upwardly from these passages7 so that the draft will contact with the fuel at the inclined surfaces. The draft is thus supplied directly to the lowermost particles of fuel which contact with the surface of the grate. and this results in more perfect combustion of these fuel particles. The cooling action of the draft on the inclined fuel-supporting surfaces tends to prevent destructive overheating of the grate. Another interesting condition lies in the fact that a fuel bed having a flat top surface will he deepest at the inclined faces where the draft .is admitted, and this is desirable because it result-s in a more uniform distribution of the draft.

Fig. I is a longitudinal section illustrating a portion of a furnace provided with a chain grate embodying the features of this invention.

Serial No. 30,667.

Fig. l1 is an enlarged perspective view of one of the grate links.

Fig. HI is an enlarged section showing a pivot rod extending through several of the links.

The .chain grate herein shown comprises grate links A connected together by means of pivot rods 1 to form an endless chain structure. A power shaft 2 at the front of the furnace is provided with a suitable number of sprocket wheels 3 vwhereby the chain grate is driven, and a similar wheel, or roll7 4 is located at therear of the grate. The draft is admitted through ports 5 to a compartment within the endless chain structure.l said compartment having a front wall 6, a rear wall 7, and a bottom wall 8loosely supported on the lower portion of the grate and provided with an upturned rear margin which engages a stationary tube 9 to prevent longitudinal displacement of said bottom wall 8. This wall 8 has openings 10 through which line ashes and the like are discharged into the lower portion of the traveling grate.

A Z-bar 11 extending around the lower margin of the draft compartment is adapted to receive loose sealing bars 12 which rest upon the bottom wall 8. As shown at 13, ashes will cooperate with the members 11 and 12 to form seals at the lower corners of the draft compartment, and similar piles of ashes will he formed at the edges of the discharge openings 10.

Fuel is Supplied through a hopper 14 above the front portion of the traveling grate, and the ashes are discharged at the rear where the grate moves downwardly at the roll 4. The fine ashes dropping from the fuel supporting portion of the grate will fall through the draft compartment and pass out through openings 1() to the lower portion of the traveling grate. The ashes in this portion of the grate are discharged where the links move upwardly in passing around. the sprocket wheels irl. The lower port-ion ofthe grate slides over the top of a.

Y2st and inclined fuel-supporting faces 25 extending downwardly from said top face to said side faces. rlhe bosses 2l are wide enough to form separating members where-v by the vertical side faces 2% of adjacent links are spaced apart to provide draft passages between them.

The elongated grate links are arranged lengthwise of the grate, and the draft passages between the faces 24 are formed longitudinally of the grate. The draft is forced upwardly through these passages and effectively distributed through the fuel bed. This draft is transmitted directly to the fuel particles contacting with the inclined faces 25, and the draftV pressure is greatest at the deepest portions of the fuel bed which lie immediately above the draft inlets.

In this construction, the draft is an effective cooling medium for the fuel-supporting portion of the grate, and the several advantages can be obtained by using simple and inexpensive grate links. Each of the links herein shown is preferably a single casting wherein the vertical web 20, bosses 21 and fuel-supporting ribs 22 are formed integral with each other.

I claim:

A chain grate comprising grate links pivotally connected together and havin@ solid ribs at their upper margins, the side faces of adjacent ribs being separated to form draft passages, the top of each of said solid ribs being provided with a narrow, elongated and substantially horizontal fuel-supporting surface extending longitudinally of the grate, and each of said solid ribs being provided with inclined fuel-supporting surfaces extending downwardly from opposite sides of said narrow fuel-supporting surface to the side faces of the rib.

In testimony that I claim the foregoing I hereunto affix my signature.

VILLIAM M. DUNCAN. 

